PI plus one

Given promising results with some boosted-protease inhibitor (PI) monotherapy regimens, researchers have also explored two-drug regimens containing a boosted PI plus a single nucleoside reverse transcriptase inhibitor (NRTI), instead of the usual dual NRTI backbone.

In the open-label Kalead-1 study, 152 participants were randomly assigned to receive either lopinavir/ritonavir plus tenofovir or lopinavir/ritonavir plus two NRTIs chosen by the study investigators.

After 48 weeks, viral suppression below 50 copies/ml was equally likely in both arms (about 50%), but more participants in the dual therapy arm experienced small, transient viral load ‘blips’. CD4 cell increases were larger in the dual therapy group. The frequency of side-effects and proportions of patients stopping therapy were similar in both arms, although there was a non-significant trend toward a lower incidence of blood lipid elevations in the dual therapy group.¹

While several studies have produced promising results using this unorthodox approach, current UK and US treatment guidelines do not recommend dual drug therapy for patients initiating treatment or seeking a simpler regimen.